/*************************************************************************/
/*  context_gl_x11.cpp                                                   */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
/*                    http://www.godotengine.org                         */
/*************************************************************************/
/* Copyright (c) 2007-2017 Juan Linietsky, Ariel Manzur.                 */
/*                                                                       */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the       */
/* "Software"), to deal in the Software without restriction, including   */
/* without limitation the rights to use, copy, modify, merge, publish,   */
/* distribute, sublicense, and/or sell copies of the Software, and to    */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions:                                             */
/*                                                                       */
/* The above copyright notice and this permission notice shall be        */
/* included in all copies or substantial portions of the Software.       */
/*                                                                       */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
/*************************************************************************/
#include "context_gl_x11.h"

#ifdef X11_ENABLED
#if defined(OPENGL_ENABLED) || defined(LEGACYGL_ENABLED)
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>

#define GLX_GLXEXT_PROTOTYPES
#include <GL/glx.h>
#include <GL/glxext.h>

#define GLX_CONTEXT_MAJOR_VERSION_ARB		0x2091
#define GLX_CONTEXT_MINOR_VERSION_ARB		0x2092

typedef GLXContext (*GLXCREATECONTEXTATTRIBSARBPROC)(Display*, GLXFBConfig, GLXContext, Bool, const int*);

struct ContextGL_X11_Private {

	::GLXContext glx_context;
};

void ContextGL_X11::release_current() {

	glXMakeCurrent(x11_display, None, NULL);
}

void ContextGL_X11::make_current() {

	glXMakeCurrent(x11_display, x11_window, p->glx_context);
}

void ContextGL_X11::swap_buffers() {

	glXSwapBuffers(x11_display,x11_window);
}

/*
static GLWrapperFuncPtr wrapper_get_proc_address(const char* p_function) {

	//print_line(String()+"getting proc of: "+p_function);
	GLWrapperFuncPtr func=(GLWrapperFuncPtr)glXGetProcAddress( (const GLubyte*) p_function);
	if (!func) {
		print_line("Couldn't find function: "+String(p_function));
	}

	return func;

}*/

static bool ctxErrorOccurred = false;
static int ctxErrorHandler( Display *dpy, XErrorEvent *ev )
{
    ctxErrorOccurred = true;
    return 0;
}

Error ContextGL_X11::initialize() {


	GLXCREATECONTEXTATTRIBSARBPROC glXCreateContextAttribsARB = NULL;

//	const char *extensions = glXQueryExtensionsString(x11_display, DefaultScreen(x11_display));

	glXCreateContextAttribsARB = (GLXCREATECONTEXTATTRIBSARBPROC)glXGetProcAddress((const GLubyte*)"glXCreateContextAttribsARB");

	ERR_FAIL_COND_V( !glXCreateContextAttribsARB, ERR_UNCONFIGURED );


	static int visual_attribs[] = {
	    GLX_RENDER_TYPE, GLX_RGBA_BIT,
	    GLX_DRAWABLE_TYPE, GLX_WINDOW_BIT,
	    GLX_DOUBLEBUFFER, true,
	    GLX_RED_SIZE, 1,
	    GLX_GREEN_SIZE, 1,
	    GLX_BLUE_SIZE, 1,
	    GLX_DEPTH_SIZE, 24,
	    None
	};

	int fbcount;
	GLXFBConfig *fbc = glXChooseFBConfig(x11_display, DefaultScreen(x11_display), visual_attribs, &fbcount);
	ERR_FAIL_COND_V(!fbc,ERR_UNCONFIGURED);

	XVisualInfo *vi = glXGetVisualFromFBConfig(x11_display, fbc[0]);

	XSetWindowAttributes swa;

	swa.colormap = XCreateColormap(x11_display, RootWindow(x11_display, vi->screen), vi->visual, AllocNone);
	swa.border_pixel = 0;
	swa.event_mask = StructureNotifyMask;

	/*
	char* windowid = getenv("GODOT_WINDOWID");
	if (windowid) {

		//freopen("/home/punto/stdout", "w", stdout);
		//reopen("/home/punto/stderr", "w", stderr);
		x11_window = atol(windowid);
	} else {
	*/
		x11_window = XCreateWindow(x11_display, RootWindow(x11_display, vi->screen), 0, 0, OS::get_singleton()->get_video_mode().width, OS::get_singleton()->get_video_mode().height, 0, vi->depth, InputOutput, vi->visual, CWBorderPixel|CWColormap|CWEventMask, &swa);
		ERR_FAIL_COND_V(!x11_window,ERR_UNCONFIGURED);
		XMapWindow(x11_display, x11_window);
		while(true) {
			// wait for mapnotify (window created)
			XEvent e;
			XNextEvent(x11_display, &e);
			if (e.type == MapNotify)
				break;
		}
		//};


	int (*oldHandler)(Display*, XErrorEvent*) =
		     XSetErrorHandler(&ctxErrorHandler);


	if (!opengl_3_context) {
		//oldstyle context:
		p->glx_context = glXCreateContext(x11_display, vi, 0, GL_TRUE);
	} else {
		static int context_attribs[] = {
			GLX_CONTEXT_MAJOR_VERSION_ARB, 3,
			GLX_CONTEXT_MINOR_VERSION_ARB, 3,
			GLX_CONTEXT_FLAGS_ARB        , GLX_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB/*|GLX_CONTEXT_DEBUG_BIT_ARB*/,
			None
		};

		p->glx_context = glXCreateContextAttribsARB(x11_display, fbc[0], NULL, true, context_attribs);
		ERR_EXPLAIN("Could not obtain an OpenGL 3.3 context!");
		ERR_FAIL_COND_V(ctxErrorOccurred || !p->glx_context,ERR_UNCONFIGURED);
	}

	XSync( x11_display, False );
	XSetErrorHandler( oldHandler );

	print_line("ALL IS GOOD");

	glXMakeCurrent(x11_display, x11_window, p->glx_context);

	/*
	glWrapperInit(wrapper_get_proc_address);
	glFlush();

	glXSwapBuffers(x11_display,x11_window);
*/
	//glXMakeCurrent(x11_display, None, NULL);

	XFree( vi );
	XFree( fbc );

	return OK;
}

int ContextGL_X11::get_window_width() {

	XWindowAttributes xwa;
	XGetWindowAttributes(x11_display,x11_window,&xwa);

	return xwa.width;
}

int ContextGL_X11::get_window_height() {
	XWindowAttributes xwa;
	XGetWindowAttributes(x11_display,x11_window,&xwa);

	return xwa.height;
}

void ContextGL_X11::set_use_vsync(bool p_use) {
	static bool setup = false;
	static PFNGLXSWAPINTERVALEXTPROC glXSwapIntervalEXT = NULL;
	static PFNGLXSWAPINTERVALSGIPROC glXSwapIntervalMESA = NULL;
	static PFNGLXSWAPINTERVALSGIPROC glXSwapIntervalSGI = NULL;

	if (!setup) {
		setup = true;
		String extensions = glXQueryExtensionsString(x11_display, DefaultScreen(x11_display));
		if (extensions.find("GLX_EXT_swap_control") != -1)
			glXSwapIntervalEXT  = (PFNGLXSWAPINTERVALEXTPROC) glXGetProcAddressARB((const GLubyte*)"glXSwapIntervalEXT");
		if (extensions.find("GLX_MESA_swap_control") != -1)
			glXSwapIntervalMESA = (PFNGLXSWAPINTERVALSGIPROC) glXGetProcAddressARB((const GLubyte*)"glXSwapIntervalMESA");
		if (extensions.find("GLX_SGI_swap_control") != -1)
			glXSwapIntervalSGI  = (PFNGLXSWAPINTERVALSGIPROC) glXGetProcAddressARB((const GLubyte*)"glXSwapIntervalSGI");
	}
	int val = p_use ? 1:0;
	if (glXSwapIntervalMESA) {
		glXSwapIntervalMESA(val);
	}
	else if (glXSwapIntervalSGI) {
		glXSwapIntervalSGI(val);
	}
	else if (glXSwapIntervalEXT) {
		GLXDrawable drawable = glXGetCurrentDrawable();
		glXSwapIntervalEXT(x11_display, drawable, val);
	}
	else return;
	use_vsync = p_use;
}
bool ContextGL_X11::is_using_vsync() const {

	return use_vsync;
}


ContextGL_X11::ContextGL_X11(::Display *p_x11_display,::Window &p_x11_window,const OS::VideoMode& p_default_video_mode,bool p_opengl_3_context) : x11_window(p_x11_window) {

	default_video_mode=p_default_video_mode;
	x11_display=p_x11_display;

	opengl_3_context=p_opengl_3_context;

	double_buffer=false;
	direct_render=false;
	glx_minor=glx_major=0;
	p = memnew( ContextGL_X11_Private );
	p->glx_context=0;
	use_vsync=false;
}


ContextGL_X11::~ContextGL_X11() {
	release_current();
	glXDestroyContext( x11_display, p->glx_context );

	memdelete( p );
}


#endif
#endif
